The application proposes to identify genes responsible for an autosomal dominant form of idiopathic ventricular fibrillation, the Brugada Syndrome. PI is following up the identification of mutations in a cardiac sodium channel gene (SCN5A) in three families with this disorder. Other families are NOT linked to SCN5A and so the PI proposes to map them by linkage, assess candidate genes (channel protein genes) if they map to the appropriate location, do fine mapping and physical mapping and gene isolation by positional cloning and positional EST candidate approaches. If pathogenic mutations are found, he proposes to collaborate in expressing them in frog oocytes to study the effect of the mutations on ion fluxes and action potentials.